The present invention relates to a gas burner for a cooking hob, intended to be used advantageously in any type of gas cooker, in particular of the household type, for cooking food products.
As is known, burners are conventionally mounted on cooking hobs, opposite gas injection nozzles.
In greater detail, each burner is formed by a plurality of components which can be separated from each other and suitably assembled so as to form the burner as a single unit which allows in particular correct mixing between the air and gas and consequent optimum combustion of the mixture thus obtained.
In accordance with the art known hitherto, each burner is conventionally composed of a bowl (or cup) fixed to the cooking hob and provided on the bottom with a gas injection nozzle, a mushroom-shaped burner body which can be inserted inside the cup and a flame-dividing element which can be mounted on the burner body and associated at the top with a top piece.
The burner body, in turn, is conventionally composed of a hollow axial shank provided with a plurality of side openings for entry of the air and by an overlying disk-shaped portion having an annular seat for receiving the flame-dividing element. The latter is of a type known per se and is provided with a series of orifices for the outflow of the air/gas mixture.
During operation, the shank is inserted inside the cup until the bottom surface of the disk-shaped portion rests against the top of the said cup.
As is known, moreover, the shank generally has a frustoconical shape with a bottom opening having a smaller cross-section arranged in a position facing the gas-injection nozzle. In this way, the flow of gas inside the shank causes a Venturi effect with consequent drawing of primary air via the side openings.
Essentially all the burners of the known type perform air/gas mixing by means of the Venturi effect using a tubular element which is positioned vertically with respect to the burner and in line with the outflow of the gas from the nozzle.
Numerous configurations of burners with different arrangements of the openings for the flow of the primary air intended to be mixed with the gas supplied from the nozzle are known. In particular, a burner configuration is known whereby the shank is arranged facing the nozzle at a certain distance therefrom so as to allow air to be drawn directly through the bottom opening of the shank.
This latter burner embodiment is described and illustrated in European patent EP-B-0,485,645.
Burners in which the flame-dividing element forms a single body with the burner body are also known, being made as one piece by means of a die-casting process. In this case the disk-shaped portion of the burner body incorporates the flame-dividing element in a single unit.
In practice, the burners of the known type, described in brief above, have numerous drawbacks.
A major drawback of these burners of the known type consists in the fact that they have a large number of constructional components. This fact means that a not insignificant amount of time is required in order to assemble the individual components as a single unit. Moreover, often an excessive amount of time is required in order to assemble burners of the known type on the cooking hobs.
The presence of numerous constructional components also poses an intrinsic operational difficulty every time it is required to assemble or disassemble the burner, for example for maintenance or routine cleaning purposes.
A further drawback of burners of the known type consists in the fact that the production of the individual components is performed by means of die-casting processes which per se are complex and such that they increase the overall production costs of burners of the known type.
Generally, moreover, these components are made of pressure-cast aluminium which, as is known, has a limited duration over time, among other things being able to be easily corroded by the cleaning agents which are widely used.
All these disadvantages therefore constitute an obvious limitation of the burners of the known type which may have a significant negative effect on the entire burner manufacturing process.
It should be noted, finally, that, owing to the vertical insertion of a Venturi tube, the height of the burner may result in an excessive volume occupied by the burner on the cooking hob.
The main object of the present invention is therefore that of eliminating the drawbacks of the prior art mentioned above by providing a gas burner for a cooking hob, which is simple and inexpensive to manufacture and allows rapid assembly of its constructional components.
Another object of the present invention is to provide a gas burner which is easy to assemble and/or disassemble and which allows rapid maintenance and cleaning operations.
Another object of the present invention is to provide a gas burner which has small overall dimensions with, in particular, a low height.
Another object of the present invention is to provide a gas burner which has a small number of constructional components.
Another object of the present invention is to provide gas burner which is long-wearing over time and which is made of material able to resist the cleaning agents which are commonly used.
A further object of the present invention is to provide a burner which is simple from a constructional point of view and operationally entirely reliable.
These objects, together with others, are all achieved by the gas burner for a cooking hob which, in accordance with the present invention, comprises a burner body provided with at least one opening for entry of primary air, a flame-dividing element defining together with the burner body an air/gas mixing chamber, a gas injector intended to be mounted on the cooking hob in order to inject gas inside the mixing chamber, and a converging/diverging duct defining a Venturi tube located downstream of the gas injector for drawing air into the mixing chamber, characterized in that he burner body, the flame-dividing element and the converging/diverging duct consist of a monolithic structure in the form of a pressed sheet-metal casing.
As a result of this gas burner the number of constructional components is reduced, allowing more economical and faster and simpler assembly.